Fastening element

ABSTRACT

A fastening element, which is used in particular in mines and/or tunnel construction, includes an anchoring tube ( 2 ), a squeezable-out, one-or multicomponent chemical mass contained in a foil bag ( 5;25 ) arranged in the anchoring tube ( 2;2 ) between spaced from each other, first stop ( 7,27 ) and second stop ( 9 ), and at least one pressure application element ( 14 ) arranged between the first stop ( 7,27 ) and/or the second stop ( 9 ) and a respective axial end region ( 11,12;31 ) of the foil bag ( 5;25 ) for applying pressure to the foil bag ( 5;25 ) in a shelf condition of the fastening element ( 1;21 )

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fastening element, in particular for use in mine and/or tunnel constructions and including an anchoring tube having first and second ends, and a squeezable-out one-or multicomponent chemical mass which is contained in a foil bag arranged in the anchoring tube between spaced from each other, first and second stops.

2. Description of Prior Art

Fastening elements, in particular for use in mine and tunnel construction are generally known. They are used primarily as roof bolts for stabilization of wall of hollow spaces of tunnels, galleries and the like. The wall-forming, following each other rock strata are secured to each other with fastening elements. Because in many cases layers, which lie in an immediate vicinity of the wall surface, have reduced mechanical characteristics, in particular their bearing capacity, as a result of formation of hollow spaces, the immediately adjacent to the wall surface, layers or strata are secured to further located, undamaged layers or strata.

German Publication DE-100 17 250 AI discloses a fastening element of the type described above and including an anchoring tube which is provided at one of its end with a drilling head and at an opposite end with engagement means, e.g., for a drilling tool. A foil bag, which contains a squeezable-out, one-or multicomponent mass, is arranged in the anchoring tube between spaced from each other, first and second stops. The first stop is formed in the region of the first end of the anchoring tube by a mixing element, and the second stop is formed in the region of the second end of the anchoring tube by a pressing-out piston. The fastening element is formed of separate elements. The drilling head has at least one outlet channel for delivery of the chemical mass. The setting process of the known fastening element is effected in two steps. In the first step, the fastening element is drilled, e.g., with a drilling tool in underground, in particular, rock. The removed, comminuted stone, which is produced by the drilling head of the fastening element, is removed through the intermediate space between the wall of the bore and the outer circumference of the fastening element. In a second step, the piston, which is provided at the second end of the anchoring tube remote from the setting direction end of the anchoring tube, is pressed further into the anchoring tube, squeezing the chemical mass, which is stored in the foil bag located in the anchoring tube, out into the bore through the outlet channel that is provided in the drilling head.

The drawback of the fastening element which is disclosed in DE-100 17 750AI, consists in that, in particular, during a long shelf time of a fastening element, loss of the chemical mass takes place as a result of a diffusion process in or through the foil and, e.g., through the ends of the foil bag which are closed with clips. During dispensing of the mass from the foil bag, the bag can fold, obstructing or impairing the dispensing process. When multicomponent masses are contained in a foil bag, the folding of the foil bag can distort the mixing ratio of the components during the dispensing process. This behavior of the foil bag leads to a prohibitive bearing behavior of the fastening element or even to a total collapse of the fastening element.

Accordingly, an object of the invention is to provide a fastening element that can be perfectly set even after an extended shelf life.

SUMMARY OF THE INVENTION

This and other objects of the present invention, which will become apparent hereinafter, are achieved, according to the invention, by providing at least one pressure application element arranged between the first stop and/or the second stop and a respective axial and region of the foil bag for applying pressure to the foil bag in a shelf condition of the fastening element.

The at least one pressure application element applies a permanent pressure to the chemical mass contained in the foil bag. As a result, the foil of the foil bag is always deformed outwardly, so that no hollows are formed in the foil bag, and no folding of the foil bag during the squeezing-out or dispensing process takes place. The pressure application element can be provided, e.g., between the first stop and the end region of the foil bag adjacent to the first stop. Alternatively, the pressure application element can be provided between the second stop and the end region of the bag adjacent to the second stop. Also, a pressure application element can be provided between each of the stops and a respective end of the foil bag.

Advantageously, as a pressure application element, a spring is used. The spring characteristic and the length of the spring are so selected that during the entire predetermined shelf life of the fastening element and the necessary tensioning displacement, a sufficient pressure is applied to the foil bag and, thus, to the chemical mass. Advantageously, as a spring, a helical spring is used which is made, e.g., from spring steel. The dispensing means, e.g., a pressing-out piston can, if needed, penetrate through the spring, without the biasing force or the pressure applied to the foil bag being reduced during the penetration of the dispensing means through the spring and an effective beginning of the dispensing process.

Instead of a spring, as a pressure application element, a pressurized body, e.g., a gas-filled body or a body, which is filled with a suitable fluid, can be provided between the first and/or the second stop and a respective axial end region of the foil bag for applying pressure to the foil bag in the shelf condition of a fastening element. A ball-shaped body, e.g., can have, advantageously, a destructible diaphragm which becomes destroyed, directly or indirectly, during the dispensing process by the dispensing device.

Preferably, the first stop is formed by a section of a drilling head. The drilling head is secured at the first end of the anchoring tube, with the first stop-forming section of the drilling head extending into the anchoring tube. If the pressure application element is allanged between the stop-forming section of the drilling head and the adjacent thereto, end region of the foil bag, the pressure application element can be supported against the drilling head. If the pressure application element is provided between, the second stop and the adjacent thereto, end region of the foil bag, the foil bag, to which the pressure is applied, is supported against the stop-forming section of the drilling head. With the second arrangement, the region of the drilling head, which is adjacent to the foil bag, advantageously, has a recess for receiving a corresponding region of the foil bag, so that the foil bag can flatly abut the support surface.

Alternatively, the first stop can be formed by mixing means in which the separate components, which are squeezed out of the foil bag, are used to form a finished chemical mass. The mixing means is generally arranged between the drilling head and an adjacent region of the foil bag, with the foil bag being supported against the mixing means. The mixing means has an appropriate receptacle for receiving the respective end region of the foil bag so that the end region is flatly supported in the receptacle. When the pressure application element is located at the mixing means, it can be supported thereagainst.

Advantageously, the second stop is formed by a centering element. The centering element aligns, e.g., the foil bag or a foil bag-receiving member, such as inner tube, and retains the foil bag or the foil bag-receiving member, during storage or during the setting process, in the predetermined position in the anchoring tube. When a foil bag-receiving member is used, an annular gap is provided between the outer wall of the foil bag-receiving means and the inner wall of the anchoring tube, which annular gap provides for removal, e.g., by suction, of drillings which are produced during the drilling process, or for feeding fluid to the drilling head. The centering element is mounted on the second end of the anchoring tube, with a section of the centering element extending into the anchoring tube. In case, the pressure application element is arranged between the section of the centering element which extends into the anchoring tube and the adjacent end region of the foil bag, the pressure application element can be supported against the centering element. In case the pressure application element is arranged between the first stop and the foil bag, it is the foil bag that is supported against the centering element. In the later case, the centering element has a receptacle for receiving the foil bag and which is so formed that the foil bag is flatly received in the receptacle.

Advantageously, the at least one pressure application element is arranged between the second stop and the adjacent end region of the foil bag. With this arrangement, during the dispensing process, the foil bag is always folds away from its end to which pressure is applied, so that an undesirable collapse of the foil bag is reliably prevented. Advantageously, the end region of the foil bag adjacent to the pressing-out piston is surrounded by the piston at least region wise, with the pressure application element being supported against the piston.

The novel features of the present invention, which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiments, when read with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings show:

FIG. 1 a longitudinal cross-sectional view of a first embodiment of a fastening element according to the present invention; and

FIG. 2 a longitudinal cross-sectional view of a second embodiment of a fastening element according to the present invention.

In both Figures, the same element are designated with the same reference numerals.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A fastening element 1 according to the present invention, a first embodiment of which is shown in FIG. 1, includes an anchoring tube 2 having a first end 3 and a second end 4, and a foil bag 5 containing a one-component chemical mass. A drilling head 6 is secured on the first end 3 of the anchoring tube 2. The drilling head 6 forms the first stop 7 for the foil bag 5. A centering element 8 is pressed into the second end 4 of the anchoring tube 2. The centering element 8 forms a second stop 9 for the foil bag 5. The drilling head 6 has a receiving section 10 for supporting an axial and region 11 of the foil bag 5 adjacent to the first stop 7. In order to facilitate squeezing the chemical mass out, there is provided, at the second end region 12 of the foil bag 5 adjacent to the second stop 9, a pressing-out piston 13.

Between the pressing-out piston 13 and the centering element 8, there is provided a helical spring 15 that functions as pressure application means 14 for applying pressure to the foil bag 5 both in shelf condition of the fastening element 1 and during a setting process when the fastening element 1 is being set in. The spring characteristic and the length of the helical spring 15 are so selected that with a diameter of the foil bag 5 of from 5 to 20 mm and a follow-up displacement path of 80 mm and more, a pressure applied by the helical spring 15 to the foil bag 5 is in a range from 5 kg to 10 kg.

A fastening element 21 according to a second embodiment of the present invention, which is shown in FIG. 2, is substantially similar to the fastening element shown in FIG. 1, so that many of the above-discussed elements are also present in the fastening element 21. In distinction from the fastening element 1, the anchoring tube 22 of the fastening element 21 is filled with a multicomponent chemical mass that is stored in a foil bag 25. The components of the chemical mass are mixed, during the squeezing-out process and before exciting the drilling head 26, to a finished mass in a mixing device 36. The first stop 27 for the axial end region 31 of the foil bag 25 adjacent to the mixing device 36, is formed by a receptacle 30 of the mixing device 36. As in the fastening element 1, pressure application means 14, which is formed as the helical spring 15, is arranged between the pressing-out piston 13 or the axial end region 12 of the foil bag 12 and the centering element 8.

Though the present invention was shown and described with references to the preferred embodiments, such are merely illustrative of the present invention and are not to be construed as a limitation thereof, and various modifications of the present invention will be apparent to those skilled in the art. It is, therefore, not intended that the present invention be limited to the disclosed embodiments or details thereof, and the present invention includes all variations and/or alternative embodiments within the spirit and scope of the present invention as defined by the appended claims. 

1. A fastening element, comprising an anchoring tube (2;22) having a first end (3) and a second end (4); a squeezable-out, one-or multicomponent chemical mass contained in a foil bag (5;25) arranged in the anchoring tube (2;22) between spaced from each other, first stop (7,27) and second stop (9); and at least one pressure application element (14) arranged between one of the first stop (7,27) and the second stop (9) and a respective axial end region (11,12;31) of the foil bag (5;25) for applying pressure to the foil bag (5;25) in a shelf condition of the fastening element (1;21).
 2. A fastening element according to claim 1, wherein the at least one pressure application element (14) is formed as a spring element.
 3. A fastening element according claim 2, wherein the spring element is formed as a helical spring (15).
 4. A fastening element according to claim 1, further comprising a drilling head (6) provided at the first end (3) of the anchoring tube (2), wherein the first stop (7) is formed by a section of the drilling head (6).
 5. A fastening element according to claim 1, wherein the first stop (27) is formed by mixing means (36) provided at the first end (3) of the anchoring tube (2).
 6. A fastening element according to claim 1, wherein the second stop (9) is formed by a centering element (8) provided at the second end (4) of the anchoring tube (2).
 7. A fastening element according to claim 1, wherein the at least one pressure application element (14) is provided between the second stop (9) and the adjacent thereto, end region (12) of the foil bag (5;25). 